Post Traumatic Stress Disorder (PTSD) is a plausible biological mechanism for complications and poor outcomes of childbearing both via associated high-risk behaviors and via neuroendocrine pathways. Despite the high prevalence of PTSD among women, there has been almost no research evaluating the potential adverse effects of PTSD on childbearing. Preliminary epidemiological work suggests that PTSD during pregnancy is associated with ectopic pregnancy, spontaneous abortion, hyperemesis, preterm contraction episodes, and concerns about fetal weight gain. The central hypothesis for this project is that PTSD is associated with adverse outcomes from early pregnancy through the postpartum period. The Aims are: 1. To determine the extent to which PTSD is associated with adverse outcomes of childbearing by comparing 3 cohorts: PTSD-diagnosed, trauma-exposed, and non-exposed pregnant women. 2. To determine via a chronobiological analysis whether the low cortisol levels associated with PTSD in non-pregnant women also occur in the hormonal context of pregnancy. 3. To determine the extent to which this Iow-cortisol biological correlate of PTSD also is associated with adverse outcomes. A prospective, psychobiological, multiple-cohort design will be used with 1230 pregnant women, with a subset of 114 to give salivary cortisol specimens throughout the course of the pregnancy. Prenatal and postpartum interviews will measure variables from the conceptual framework, including trauma history, PTSD diagnosis, health risk behaviors, psychiatric comorbidity, pregnancy factors, demographics, potential moderators including chronic stress, prenatal care and mental health treatment, and 2 psychological outcomes, postpartum depression and attachment disorder. Other adverse outcomes will be determined from medical record review. Findings from this study will provide a strong basis for future clinical research and an evidence base for potentially modifying maternity care practice guidelines to include care for PTSD.